Overweight, Smoking: New Potential Causes Of Stomach Cancer Uncovered - Know Key Trigger Factors

Stomach cancer, also known as gastric cancer, occurs when a malignant tumour or cancerous growth develops in the mucosa or lining of the stomach.

The incidence of gastric cancer in India is lower compared to other developed countries. However, the National Institutes of Health (NIH) reveals that stomach cancer is the “fifth most common cancer among males and seventh most common cancer among females in India.”

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Stomach cancer is the fifth most common cancer globally

The World Cancer Research Fund ranks stomach cancer as the fifth most common cancer globally.

To explore one of the leading causes of cancer-related deaths, researchers from three institutes namely - Wellcome Sanger Institute, Broad Institute of MIT and Harvard, and The University of Hong Kong (HKU), along with their collaborators, conducted a study by collecting samples of normal stomach lining from individuals with and without gastric cancer.

Method of the findings

To understand how normal and cancerous stomach cells grow over time, researchers used the whole-genome sequencing method to examine 238 tissue samples from 30 people including 18 with gastric cancer and 12 with no gastric pathology.

New findings

In a publication released on March 19 by Nature, it states, “Surveying 829 polyclonal gastric microbiopsies by targeted sequencing, we find somatic ‘driver’ mutations in a distinctive repertoire of known cancer genes, including ARID1A, ARID1B, ARID2, CTNNB1 and KDM6A.”

“By studying somatic mutations in normal tissues, which we acquire over our lifetimes, we can explore the earliest stages of cancer development. We found that despite constant exposure to acidic stomach contents, the stomach lining is protected. However, in those with gastric cancer, we see higher numbers of mutations in normal cells, resembling the earliest stages of stomach cancer. This research adds to a mutation map of the gastrointestinal tract, including the oesophagus, stomach, small intestine and colon, to compare mutation rates and mutational processes across the body,” explains Dr Tim Coorens, the first author previously at the Wellcome Sanger Institute and now at the Broad Institute of MIT and Harvard.

The study also found out how some stomach linings had three copies of certain chromosomes and others did not.

Professor Suet Yi Leung, co-lead author at the University of Hong Kong highlights, “We discovered an unusual phenomenon, where some individuals had three copies of certain chromosomes – known as trisomy – whereas others did not. We’ve not seen this in any other tissue, and it hints towards an unknown, external mutagen that only some of these people may have been exposed to.”

Some known risk factors that contribute to gastric cancer include infection with Helicobacter pylori and Epstein-Barr virus, excessive alcohol consumption, tobacco use, obesity, and diet.

The study found that cancer risks and the influence of various risk factors differ significantly between different anatomical regions of the stomach, with the highest risks in the antrum in high-incidence areas and the cardia in low-incidence areas.

Examination of stomach cancer suggests that exposure to certain factors and chronic inflammation lead to somatic mutagenesis in the stomach.